Field of the Invention:
The present invention relates to a method for absorbing or dissipating energy to damp loads during an overload event in particular on a loading unit for transporting objects, in order to protect the objects being transported, such as persons or items, from being damaged. Said single overload event occurs when a mine detonates.
Different methods are known for absorbing energy in order to reduce loads during overload events, such as explosions underneath armoured vehicles, to protect the objects being transported, in particular persons and sensitive devices. Typically, mechanical systems are used for protection which absorb energy by being deformed or torn open in order to absorb energy and protect passengers correspondingly during an overload event.
However, their disadvantage is that with said systems it is impossible to control the damping or energy absorption during an overload event when its impulse intensity and progression are unknown. The intensity and duration of the impulse caused by mine explosions cannot be predicted before the explosion, since the type and power of the mine, the place, its exact positioning, its depth in the soil and the material surrounding the mine are unknown during a real overload event. Monitoring and evaluating the speed of the vehicle or other parameters before the overload event occurs, i.e. before the explosion of a mine, does not enable any estimate to be made about the power of an explosion. Therefore, it is impossible to exactly plan the process of the energy absorption during an overload event before said event occurs.
A method for regulating an energy absorber of a steering column is known in WO 2011/141164 AI, wherein a sensor measures the relative velocity of parts which are movable relative to one another. The energy absorber is then controlled in such a way that the delay is as constant and low as possible, so that the relative velocity of the parts that are movable relative to one another is close to 0 at the end of their movement path. Moreover, this document also indicates the possible use of said energy absorber in safety belt assemblies, mine blast protection seats, bumpers, tool machinery, arresting gear for aircraft landing on aircraft carriers, damping systems for helicopters and damping systems for shoes. Said method, wherein the energy absorber is controlled in such a way that the relative movement of the parts of the energy absorber that are moveable relative to one another is slowed down to 0 at the end of their movement path, can only be carried out if the parameters are known beforehand. If a vehicle on the road drives into the back of a car in front of it, the relative velocity can be directly determined and the entire vertical lift can be optimally used to specifically slow down the relative movement. The same applies to arresting gear for an aircraft landing on an aircraft carrier and even to helicopter crashes, where drop height and drop velocity are known.
Each of the applications makes optimal use of the maximum movement path in order to enable the load to be preferably minimal, e.g. during a car crash, so that the driver experiences the lowest possible force when colliding with the steering column. Such a system works well for regulating the energy absorber in steering columns or in other applications, for which the velocities occurring and consequently the loads are known and, accordingly, the available movement path can be correlated with the current relative velocity.
In applications in mine blast protection seats, for example, when the strength of the explosion is unknown, as it is when a mine explodes underneath an armoured vehicle, said regulation can yield the desired results if the explosion is weak. The forces being applied can be damped and passed on to the body of a person seated on the mine blast protection seat. The load can be reduced considerably. The delay or relative velocity is adjusted so that the load along the movement path is low and constant.
Said method requires knowledge of the initial and marginal conditions. If there are outside influences, the strength and duration of which are initially unknown, the application can lead to correspondingly unexpected results with the damping being too strong or too weak.